21354471 has 12 divisors (see below), whose sum is σ = 31268848. Its totient is φ = 14040864.

The previous prime is 21354451. The next prime is 21354551. The reversal of 21354471 is 17445312.

21354471 is a `hidden beast` number, since 213 + 5 + 447 + 1 = 666.

It is not a de Polignac number, because 21354471 - 2⁶ = 21354407 is a prime.

It is a super-3 number, since 3×21354471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354451) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15595 + ... + 16908.

Almost surely, 2^21354471 is an apocalyptic number.

21354471 is a deficient number, since it is larger than the sum of its proper divisors (9914377).

21354471 is a wasteful number, since it uses less digits than its factorization.

21354471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32582 (or 32579 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21354471 is about 4621.0898065283. The cubic root of 21354471 is about 277.4360797504.

Adding to 21354471 its reverse (17445312), we get a palindrome (38799783).

The spelling of 21354471 in words is "twenty-one million, three hundred fifty-four thousand, four hundred seventy-one".